Security protocols often involve loops, such as for ratcheting or for manipulating inductively-defined data structures. However, the automated analysis of security protocols has struggled to keep up with these features. The state-of-the-art often necessitates working with abstractions of such data structures or relies heavily on auxiliary, user-defined lemmas.

In times of armed conflict, the emblems of the red cross, red crescent, and red crystal are used to mark physical infrastructure. This enables military units to identify assets as protected under international humanitarian law to avoid attacking them. In this paper, we tackle the novel security problem of how to extend such protection to digital, network-connected infrastructure through a digital emblem. A digital emblem has a unique combination of security requirements, namely, authentication, accountability, and a property that we call covert inspection. Covert inspection states that those wishing to authenticate assets as protected must be able to do so without revealing that they may attack unprotected entities.